I went to Catholic high school in Queens with a lot of first generation Polish-Americans and I was at first perplexed when the Polish joke fad started. In my experience, Poles were more like Jews in that they appeared to be a cut above the average intellectually. Physcially, they tended to atheletic, but graviated towards soccer and track rather than football and basketball.
One of Hitler's first act was to assassinate scores of Polish military minds, as a preemptive move against a formidable foe.